Pull up from trunk:
New hacks to make libc work painlessly without bumping the major number:
use type func(arg1s) asm("emitted_name") gcc mechanism.
Suggested by Bill Sommerfeld.
Allow the old-name functions to be compiled from the same source file as
the renamed functions, and add some #error directives to force the
issue with weak symbols for renamed functions when we support weak
symbols in the C library.